To provide a drive controller of single phase induction motor capable of correctly recognizing open operation of a thermal protector.
A drive controller of single phase induction motor comprises: first voltage monitoring means (15) that monitors voltage of an AC power source (1) to output a corresponding first voltage (V1); second voltage monitoring means (17) that detects voltage across a phase advance capacitor (7) to output a corresponding second voltage (V2); a comparator circuit (49) that compares the first voltage (V1) with the second one (V2). The first voltage monitoring means (15) and the second voltage monitoring means (17) are constituted in such a manner that the first and second voltages (V1, V2) satisfy a first magnitude relation (V1>V2) when a thermal protector (11) is not activated and the AC power source (1) is turned off and satisfy a second magnitude relation (V1<V2) different from the first magnitude relation when the thermal protector (11) is activated.
Arihara Koichi
Matsushima Tetsuo
Hidefumi Kawamura
Naomi Yoshida
Ayako Nakamura
Fukagawa Eri
Satoshi Morimoto
Kyoko Tsunoda
Hirose Miki